People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

The Human Brain In Numbers, From Its Weight, Neurons, And Amount Of Spinal Fluid

The human brain, also known as the "last frontier" in science, is the most formidable organ we possess. It's able to process information daily, from remembering the names of acquaintances to learning a new skill at work, but what's exactly inside our brain that makes it more powerful than a computer?

In BrainCraft's latest video, “Your Brain in Numbers,” host Vanessa Hill explains how the brain is greater than the sum of its parts. The average human brain weighs 3 pounds, and is 16.7 centimeters (cm) long, 9.3 cm high, and 14 cm wide. The organ is made up of 86 billion neurons that are able to form over one trillion connections. A piece of brain tissue, which is about the size of a grain of sand, contains 100,000 neurons and 1,000,000 synapses.

Neurons have three parts, including dendrites (body), axon (reaches out to other cells), and axon terminals (transmits a neurotransmitter from one neuron to another), that carry out the functions of communication and integration in the nervous system. The longest axon in the body is about 1 meter long and stretches from the base of the spine to the big toe. A nerve impulse is able to travel to the muscles at 120 meters per second (m/s), while pain signals travel between 0.5 and 30 m/s.

The brain contains plenty of water; it’s about 78 percent water compared to 70 percent for the whole body. Sixty percent of its dry weight is fat, making it the fattiest organ in the body. It uses 20 percent of our daily oxygen and calorie needs. The powerful brain has the capability to produce about 500 milliliters (ml) of cerebrospinal fluid per day, and reabsorbs it so 100 to 160 ml surround the brain at any given time.

It turns out our brains are truly bright. They generate 10 to 23 watts; enough to power a light bulb.